Integrated biological treatment and agricultural reuse of olive mill effluents with the concurrent recovery of energy sources (BIOTROLL)

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1 Integrated biological treatment and agricultural reuse of olive mill effluents with the concurrent recovery of energy sources (BIOTROLL) I.V. Skiadas, H.N. Gavala, G. Lyberatos, E. Pistikopoulos, C. Ciavatta and B.K. Ahring The project is funded by the European Commission (FP5, Quality of life and management of living resources Key action 5) Contract number: QLK5-CT Total budget: 1,700,000 Project duration: 36 months

2 BIOTROLL research partners EMB group, Biocentrum-DTU, Denmark Leading scientist and project coordinator: Prof. B.K. Ahring LBEET, Department of Chemical Engineering, University of Patras, Greece Leading scientist: Prof. G. Lyberatos Department of Agro-Environmental Sciences and Technology, University of Bologna, Italy Leading scientist: Prof. C. Ciavatta Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College, London Leading scientist: Prof. E.N. Pistikopoulos

3 BIOTROLL industrial partners Eleourgiki Lipasmaton, A. Karathanasis S.A., Industrial Area of Kalamata, Greece Biocontractors A.S., Lyngby, Denmark

4 What is olive pulp? Traditional three-phase olive oil producing industries Two-phase olive oil producing industries Consumption of water Generation of olive-mill wastewater No addition of water Generation of a semisolid residue called olive pulp

5 Three-phase olive oil production cold water warm water warm water olives WASHING CRUSHING MALAXING THREE-PHASE CENTRIFUGAL DECANTING cake (solid residue phase) warm water oily phase water phase warm water CENTRIFUGATION CENTRIFUGATION olive oil wastewater olive oil wastewater 1. high amout of water used 2. generation of high organic content wastewater in small scale olive mills wastewater treatment prohibitevely expensive pollution of surface and ground water

6 Two-phase olive oil production cold water olives WASHING CRUSHING MALAXING TWO-PHASE CENTRIFUGAL DECANTING olive oil sludge COLLECTION AND TRANSPORTATION oolive stones CENTRAL UNIT FOR SECONDARY OLIVE OIL TWO-PHASE EXTRACTION olive oil (secondary) TWO PHASE CENTRIFUGAL OLIVE OIL EXTRACTION (RECENTLY DEVELOPED) 1. small amout of water used 2. generation of olive pulp in large-scale central units a. useful by-product b. further investigation is needed c. 80% per dry weight carbohydrates OLIVE PULP BIOTROLL innovative and integrated management of two-phase olive mill effluents

7 CENTRAL UNIT FOR SECONDARY OLIVE OIL TWO-PHASE EXTRACTION Olive mill effluent tones / year 60% water content Warm water 50 o C Separation of Olive stones Olive stones 1500 tones / year 10% water content Heating devices Warm water 50 o C MALAXING DECANTER Olive oil phase Olive pulp 8400 tones / year 70% water content Warm water 50 o C CENTRIFUGATION Olive oil 100 tones / year

8 Research scope To combine production of olive oil with the treatment of the generated olive pulp for the production of bioenergy (in the form of CH 4, H 2 and ethanol) and fertilizer OLIVE OIL & BIOENERGY

9 Characteristics of the olive pulp Olive stones, % Water, % TS, % Total carbohydrates, g / 100 g TS Chemical Oxygen Demand, g / 100 g TS Lignin, g / 100 g TS 8.9 ± ± ± ±

10 BIOTROLL project: innovative management of two-phase olive mill effluents SSF fermentation (enzymes + Saccharomyces cerevisiae ) Thermophilic fermentation (70 o C, Thermoanaerobacter mathranii) olive pulp Pre-treatment (wet oxidation) H 2 Ethanol Ethanol olive pulp Anaerobic digestion CH 4 sludge effluent olive pulp Fermentor for hydrogen production flow diagram for ethanol production after wet oxidation of the olive pulp, followed by anaerobic digestion flow diagram for hydrogen production after wet oxidation of the olive pulp, followed by anaerobic digestion flow diagram for hydrogen production from the raw olive pulp followed by anaerobic digestion flow diagram for anaerobic digestion of the raw olive pulp

11 Bioethanol production from olive pulp Glucose Olive Pulp Cellulose + Hemicellulose Enzymatic Hydrolysis Xylose

12 Enzyme hydrolysis of olive pulp Un-treated 5 FPU/g-CEL 10 FPU/g-CEL 20 FPU/g-CEL Glucose Concentration (g/l) days 4 days 7 days Increase in Glucose Increase in Xylose 4 days 4 days 5 FPU/g-CEL 43% 15% 10 FPU/g-CEL 50% 22% 20 FPU/g-CEL 56% 27%

13 Process efficiency C 6 H 12 O 6 C 2 H 5 OH Enzyme loading Biomass Concentration Ethanol Production Ethanol Yield (FPU/g-CEL) (g-dm/l) (g/l) (g-etoh/g-glu)

14 Hydrogenogenic CSTR Active volume: 500 ml Operating conditions Temperature HRT (h) Flow rates (ml/d) Loading rates (g TS/d) 35 or 55 C

15 Hydrogen production from batch and CSTR experiments with raw olive pulp Batch experiments Olive pulp, 1:4 Olive pulp, 1:20 mmole H 2 / g TS olive pulp 1.54 ± ± 0.19 CSTR efficiency: 0.32 mmole H 2 / g TS

16 Methanogenic CSTR Active volume: 3 L Operating conditions Temperature HRT Flow rate Loading rate 35 or 55 C 20 d 150 ml/d 7 g TS/d

17 Methanogenic potential of the raw olive pulp and of the H 2 -CSTR effluent Raw olive pulp H 2 -CSTR effluent mmole CH 4 / g TS 18.5 ± ± 0.2 % TS removal 55.9 ± ± 6.8 CSTR efficiency: 14.1 mmole CH 4 / g TS raw olive pulp 39 % TS removal

18 Processes evaluated to be feasible for Pilot Testing SSF fermentation (enzymes + Saccharomyces cerevisiae ) Thermophilic fermentation (70 o C, Thermoanaerobacter mathranii) CH 4 Ethanol Ethanol raw olive pulp Pre-treatment (wet oxidation) H 2 raw olive pulp Anaerobic digestion all types of sludge effluent tested for suitability as soil improving agent and/or fertiliser (WP5) raw olive pulp Fermentor for hydrogen production flow diagram for ethanol production after wet oxidation of the olive pulp, followed by anaerobic digestion flow diagram for hydrogen production after wet oxidation of the olive pulp, followed by anaerobic digestion flow diagram for hydrogen production from the raw olive pulp followed by anaerobic digestion flow diagram for anaerobic digestion of the raw olive pulp

19 Flow diagram Pilot Plant 8 9 M 2 FT 4 FT 1 TT TT TT TT LT 3 M M 5 FT TT LT TT LT 7 M 6 FT LT Process Flow estimated to 125 l/day

20 Estimation of the fertilizer value (Euro) of raw olive pulp and pretreated olive pulp Element N P 2 O 5 K 2 O Olive Pulp Conc. (kg/ton)* Euro Effluent from Hydrogen Conc. (kg/ton) Euro Effluent from Methane Conc. (kg/ton) Euro , TOTAL amount of macronutrients and value per ton *kg of element per ton of fresh material.

21 Conclusions Olive pulp is a very promising biomass for production of biofuels 0.42 m 3 CH 4 / kg TS 0.13 m 3 CH 4 / kg olive pulp The final sludge effluent can be used as soil improving agent enhancing the process sustainability since the nutrients will be recirculated